The biological activity of the multifunctional cytokine interleukin-1 (IL-1) is mediated by its receptors. The aim of this study was to determine if an association exists between single nucleotide polymorphisms (SNPs) in the IL-1 type 1 and 2 receptor genes (IL1R1 and IL1R2) and the expression level of membrane-bound IL1Rs on subpopulations of mononuclear cells or serum levels of soluble IL-1 receptors. It was observed that healthy individuals with the genotype TT in SNP rs2234650:C.T had a lower percentage of intact CD14 1 monocytes expressing IL1R1 on their surface. The SNP rs4141134:T.C in IL1R2 has also been associated with the percentage of intact CD3 1 T cells expressing IL1R2. Keywords: interleukin-1; membrane-bound receptor; SNPs; soluble receptor INTRODUCTION Interleukin-1 (IL-1) is a cytokine involved in a wide range of physiological processes, including having a central role in the regulation of acute and chronic inflammation. 1,2 The biological effects of IL-1 (IL-1a and IL-1b) are achieved by the binding of the cytokine to the membrane-bound IL-1 type 1 receptor (IL1R1). 3,4 IL1R1 is a glycoprotein with a molecular mass of 80 kDa that is predominantly expressed on endothelial cells, smooth muscle cells, epithelial cells, hepatocytes, fibroblasts, keratinocytes, epidermal dendritic cells and T lymphocytes. 5 IL-1 binding to the extracellular domain of IL1R1 promotes the recruitment of the IL-1 receptor accessory protein, which leads to signal transduction mediated by the cytoplasmic domains of IL1R1 and IL1R2 receptors. 6 The IL-1 type 2 receptor (IL1R2) is unable to initiate signaling and only acts as a 'decoy' receptor. 3,7 IL1R2 is a glycoprotein with a molecular mass of 60 kDa that is expressed on monocytes, neutrophils, T and B lymphocytes. 8,9 Studies have also provided evidence for the existence of soluble receptors for

Background: Erythroid nuclear cells (ENC) of the bone marrow (BM) have not previously been considered as important producers of wide spectrum of haemo-and immunoregulatory cytokines. The aim of the current work was to confirm the production of the main hemo-and immunoregulatory cytokines in human ENC from BM.

The biological effects of interleukin (IL)-1 are realized through binding to specific membrane-bound receptors. The efficiency of IL-1 action depends on the number of receptors on the cell. We determined the percentage of cells that express IL-1 receptor type I (IL-1RI) and IL-1 receptor type II (IL-1RII) by flow cytometry using phycoerythrin (PE)-labelled antibodies to the IL-1Rs, and the mean absolute number of membrane-bound IL-1Rs per cell using QuantiBRITE PE calibration beads. We showed that different subpopulations of immunocompetent cells expressed different numbers of molecules of membrane-bound IL-1RI and IL-1RII. We also established that when cells were stimulated with bacterial lipopolysaccharide, there was a significant increase in the number of IL-1RI expressed, and a significant decrease in the mean number of IL-1RII molecules per cell. Determination of the mean number of membrane-bound IL-1R molecules using this protocol enables us to obtain precise and reproducible data that are necessary for full evaluation of expression levels.

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